Water-cooled cupola



Oct. 25, 1955 H. A. REECE 2,721,736

WATER-COOLED CUPOLA Filed July 21, 1951 5 Sheets-Sheet 1 INVEN TOR.EKBERT A. Reeca ATToRNEYs.

25, 1955 H. A. REECE WATER-COOLED CUPOLA 3 Sheets-Sheet 2 Filed July 21,1951 IN V EN TOR. Heeeeer A ,Reece AT TOQNEYS.

Oct. 25, 1955 H. A. REECE 2,721,736

WATER-COOLED CUPOLA Filed July 21, 1951 3 Sheets-Sheet 3 IN VEN TOR.

HEQBKT A Kzece BY United States Patent WATER-COOLED CUPOLA Herbert A.Reece, Cleveland Heights, Ohio Application July 21, 1951, Serial No.237,899

4 Claims. (Cl. 263-44) This invention relates, as indicated, towater-cooled cupolas.

It has heretofore been proposed to replace the brickwork immediatelyabove the tuyeres of a cupola by a system of cooling segments, waterbeing supplied to the segments or jackets from a common main supply, buteach jacket having a separate feed and exit for the water. Such a systemis described in some detail in an article entitled BritishInvestigations of Modified Cupola Designs, which appears on pages 86-91of the November, 1949 issue of The Iron Age.

The application of water cooling to cupola furnaces of the conventionalcylindrical or conical design has, however, not proven practical noreconomical, due, in part, to the fact that these geometrical shapesnecessitate water entering and leaving the water jackets at right anglesor nearly right angles to the direction or plane of the flow of waterthrough the jackets.

Since the water flow through the jackets is in a circular or arcuatedirection, and since the lengths of the arcs increase as the radialdistance from the axis or center of the cupola increases, the water isrequired to traverse a longer path in the back or radially-outer portionof the jacket than in the front or radially-inner portion of the jacket.This means that the water flows faster in the back portion of the jacketthan in the front portion thereof, thereby setting up layers of thermalstress which are deleterious to the jacket material.

Moreover, since the jackets are of arcuate horizontal cross-section, andare in edge-to-edge abutment with each other, a double thickness ofmetal is formed or provided at each abutment zone, thereby resulting indifferentials in heat conduction which cause burning of the segments atthe joints. Furthermore, since the segments are in circumferentialabutment with each other, the segments are not free to expand orcontract circumferentially, so that they become deformed or buckled,with consequent leaks at the joints.

When such burning or leaking necessitates replacement of a segment, itbecomes necessary to tear out a substantial portion of the cupolalining, in order to extract the faulty segment and replace it with a newsegment. It thus becomes necessary to cast rather than fabricate thesegments, leading to both expense and additional metal on the face ofthe segment, which burns to the point of equalizing conduction of theheat. A vicious cycle is therefore ever present.

I have found that the aforesaid disadvantages and shortcomings of watercooling, as applied to cupolas of conventional circular or conicaldesign, can be overcome in a relatively simple and inexpensive manner byutilizing water-cooled jackets in conjunction with a cupola ofrectangular cross-section, as disclosed, for example, in my Patent No.2,471,776.

A cupola of this rectangular shape lends itself readily to theincorporation therein of water-cooled jackets, which are of extremelysimple construction and. which can be installed and removed at a"fraction of the cost Patented Oct. 25, 1955 of installing and removingwater-cooling equipment in cupolas of circular or conventional design.

A cupola of this rectangular shape also lends itself readily to theutilization of basic refractory linings, in combination with suchwater-cooled jackets, to form the wall of the cupola above the tuyeres,because the combination, as will be presently explained, permitsexpansion of the bricks forming the refractory lining without rupturingsuch bricks.

By utilization of water-cooling devices in accordance with my invention,I am able to have the water enter and leave the jackets in substantiallythe direction or plane of the flow of water through the jackets, toavoid the setting up of layers of thermal stress which are deleteriousto the jacket material, to avoid differentials in heat conduction whichcause burning of the jackets at the joints, and to avoid deformation orbuckling of the jackets, with consequent leaks at the joints.

Other objects and advantages of the invention will become apparentduring the course of the following description, when read in conjunctionwith the drawings forming a part of this specification, and in whichlike numerals are employed throughout to designate like or correspondingparts.

In said annexed drawings,

Fig. 1 is a fragmentary vertical cross-sectional view through my cupola,utilizing a preferred combination of water jackets and refractory liningabove the tuyeres, taken on the line 1-1 of Fig. 2;

Fig. 2 is a transverse cross-sectional view, taken on the line 22 ofFig. 1;

Fig. 3 is a fragmentary cross-sectional view through one of the jackets,taken on the line 3-3 of Fig. 2, and

Fig. 4 is a view similar to Fig. 2, but showing a form of the inventionutilizing only water jackets above the tnyeres.

Referring more particularly to Figs. 1 to 3 inclusive of the drawings,the cupola will be seen to comprise an upright hollow cupola body ofsubstantially rectangular cross-section, having opposed substantiallyflat side walls 1 and 2, and opposed substantially flat end walls 3 and4. The side and end walls are formed of an outer metallic shell 5, andbelow the tuyeres, the cupola is provided with a basic refractory lining6.

Directly above the tuyeres, generally indicated by reference numeral 7,the cupola is provided at the inner portions of the side walls thereofwith upstanding watercooled jackets, and at the inner portions of theend walls, with refractory linings, the jackets and linings arranged toform a rectangle corresponding to the rectangular shape of the cupola.The jackets are designated by reference numerals 8 and 9, and thelinings by reference numerals 10 and 11.

Each jacket, which in the average installation, is about 63 inches inheight, is tapered in vertical cross-section, from a thickness of about2 inches at the bottom to a thickness of about 4 inches at the top, theouter wall 12 of each jacket being substantially vertical, but the innerwall 13 being inclined outwardly, in a downward direction, so as toprevent vertically moving drops of molten iron from impinging directlyon the inner walls of the jackets in the course of the gravitation ofsaid drops to the hearth or well of the cupola, it being understood, ofcourse, that drops ricocheting from the coke within the cupola willstrike the jackets.

Each jacket is of hollow construction, consisting of an outer wall 12,an inner wall 13, a top 14, a bottom 15, and sides or ends 16 and 17.

Each jacket also includes a series of vanes or baflles 18 and 19extending between the walls 12 and 13, and spaced from, each othervertically, the vanes 18 extending from the wall 16 to points spacedfrom the side 17, and the vanes 19 extending from the side 17 to pointsspaced fromthe side 16, thereby forming a tortuous passageway for thewater through the jacket, as indicated in Fig. 3. It will also be notedthat each vane is inclined upwardly from the side 16 or 17 from which itextends, for a purpose to be presently described.

Each jacket further includes a water inlet pipe or conduit 20 adjacentthe lower end of the side 16 thereof, and a water outlet pipe or conduit21 adjacent the upper end of the side 17 thereof. These inlet and outletpipes extend through the end walls of the cupola, and in order tocompensate for thermal expansion and contraction of the jackets,provision may be made for these pipes to slide relatively to the cupolawalls as the jackets expand or contract, or to slide relatively to thewalls of the jackets as the latter expand or contract, without, ofcourse, breaking the water-tight sea-l between the pipes and jackets.

The linings and 11 are preferably in the form of walls made from basicrefractory bricks, laid on end, and

for this purpose, bricks of magnesite, periclase, Magnex (a chemicallybonded magnesite-chrome brick), Thermag (also a magnesite-chrome brick),chrome brick, and in special cases (air-setting ramming materials ormixtures). Repairs can be effected with dolomite or magnesite ormagnesia groutings.

It will be noted that each jacket, as seen in Pig. 2, has endwiseabutment with one of the lining walls extending rectangularly thereto,but has sidewise abutment with or overlaps the other lining wall whichextends rectangularly thereto. This leaves each jacket free to expand orcontract thermally without buckling, since the overlapping end of thejacket is free to slide relatively to the adjacent lining wall duringsuch expansion or contraction.

Similarly, each lining wall, 10 and 11, has endwise abutment with one ofthe jackets extending rectangularly thereto, but has sidewise abutmentwith or overlaps the other jacket which extends rectangularly thereto.This leaves each lining Wall free to expand or contract thermallywithout buckling, cracking or spalling, since the overlapping end of thewall. is free to slide relatively to the adjacent jacket during suchexpansion or contraction.

It will further be noted that the conduits and 21 enter or leave thejacket in the direction or general plane of the jacket.

The spaces between the jackets and lining walls and the shell 5 of thecupola may be filled with a suitable granular refractory material,indicated by reference numeral 22, this material being sufiicientlyfluid to permit expansion of the jackets and lining walls without injuryto the cupola walls.

Above the water jackets and lining walls, the cupola may be lined withregular firebrick, or fireclay refractory iaterial, as indicated at 23.

The sulfur fumes at the slag hole 24 are obnoxious to the cupola workmenand are carried off to the atmosphere by a sulfur fume hood 25.

It will be apparent from the foregoing description that the waterjackets are cooled by continuous circulation of cold water through thejackets, the water entering the jackets through the inlet pipes 20 andleaving the jackets through the outlet pipes 21.

The jackets, for the reasons already stated, are free to expand andcontract thermally, without becoming distorted or buckled.

Moreover, the points at which the joints between the jackets and liningwalls are exposed to the interior of the cupola are not of doublethickness, so that differentials in heat conduction which cause burningof the jackets at the joints are avoided.

Since the water inlet and outlet pipes enter and leave the ja'ck'ets insubstantially the direction or plane of the flow of water through thejackets, and the flow of water is in straight lines, the setting up oflayers of thermal stress, which are deleterious to the jacket materialis avoided.

The flow of water through the jackets is facilitated by the upwardinclination of the vanes 18 and 19 in the direction of the water flow,and the widening in the crosssectional area of the jackets upwardlycompensates for expansion of the water as the temperature of the waterincreases during its movement from the lower to the upper portion of thejacket.

Each jacket is removable without interfering with the other jacket oreither of the lining walls.

The construction of the jacket is such as to facilitate manufacture orfabrication thereof by welding together sheets or strips of rolledsteel, thereby providing economies in manufacture, and permitting thejackets to be made from stainless or austenitic steel of any desiredthickness, in the knowledge that the lighter the steel sections used,the lesser the thermal stresses encountered.

Normally basic cupolas are operated with magnesite linings, with repairsbeing made by blowing on a magnesia compound, such as Gundol.

Such linings require spacers (cracks between the magnesite brick) totake care of expansion of the brick, and when the expansion of the brickexceeds the space allowance, rupture of the brick occurs due tocompressive forces. At times, this expansion can be cumulative, withconsequent deterioration of the brick.

The utilization of lining walls, such as the walls 10 and 11, which canexpand and contract, thermally, eliminates the need for fspacers, andprovides a number of other advantages. The walls and bricks are notsubject to rupture or deterioration. Straight brick can be used toconstruct such walls, whereas keys and arches, which are considerablymore expensive than straight brick, must be used in round cupolas. Theuse of such walls, in combination with water-cooled jackets, reduces thecost of linings, Without excessive thermal losses common to water-cooledcupolas. Moreover, the desulphurizing slag is not interfered with by thelining, and the slag basicity is controlled.

A basic cupola, as thus constructed, has the following other advantages:

(a) It cools off in very short time for repairs, due to the fact thatthe jackets do not require cooling periods.

(b) It is more economical to operate than the conventional basic cupola.

(c) The metal does not suffer from lack of temperature common towater-cooled cupolas.

(d) It does not present expansion problems common to basic cupolas inwhich the entire lining is basic.

(e) It substantially desulphurizes the iron melted to the degreeprovided by the volume of slag formed in the cupola. For example, 5.0%limestone and 50% fluorspar, charged as a flux, will desulphurize morethan 3.0% limestone and 30% fluorspar.

Referring now to Fig. 4 of the drawing, there is disclosed a modifiedform of the invention, which is similar in all respects to that shown inFigs. 1 to 3, except that in this case water-cooled jackets 10' and 11are utilized instead of the basic refractory lining Walls 10 and 11.

The water-cooled jackets 10' and 11' are of a construction similar tothat of the jackets 8 and 9 and are disposed in the same relationship,relatively to the jackets 8 and 9 as the relationship between therefractory lining walls 10 and 11 and the jackets 8 and 9 of thepreferred form of the invention.

In order to avoid spaces between the overlapping portions of the jacketsand the sides of the jackets which are overlapped, which spaces are dueto the inclination of the inner faces of the jackets, the walls 16 ofeach jacket shown in Figs. 4 and 5 may be inclined vertically to conformwith or correspond with the inclination of the faces 13.

The construction shown in Fig. 4, while not as advantageous in allrespects as that shown in Figs. 1 to 3,

may be used where a greater cooling effect is desired in the portion ofthe cupola above the tuyere level.

It is to be understood that the forms of my invention herewith shown anddescribed, are to be taken as examples of the same, and that variouschanges in the shape, size and arrangement of parts may be resorted towithout departing from the spirit of my invention, or the scope of thesubjoined claims.

Having thus described my invention, I claim:

1. In combination with a cupola of substantially rectangularcross-section having a well provided with a basic lining, water-cooledjackets lining two opposite sides of said cupola above said well, eachof said jackets being of substantially rectangular and flat form andbeing substantially parallel with the adjacent portion of the cupolashell, each jacket having a fiat outer wall, a flat inner wall spacedfrom the outer wall, a top, bottom and side walls, vanes extendingbetween and to said inner and outer walls and from one side wall topoints spaced from the other side wall, and vanes extending between andto the inner and outer walls and from the other side wall to pointsspaced from the first-named side wall, in staggered arrangementvertically with the first-named vanes, where by to provide a tortuouspassageway for water through said jacket, each jacket having water inletand outlet conduits, the axes of said conduits extending horizontally,the inlet conduit being attached to an opening in one side wall of thejacket and extending to a point externally of the cupola shell, and theoutlet conduit extending from the other side wall of the jacket to apoint externally of the cupola shell, the other opposite sides of thecupola above the well being formed of basic refractory material, one endof each of said jackets having endwise engagement with one of said otheropposite cupola sides and overlapping or sidewise engagement with theother of said other opposite sides, one end of each of said otheropposite sides having endwise engagement with one of said water jacketsand overlapping or sidewise engagement with the other of said waterjackets, whereby each of said jackets and sides is free to expand orcontract without interfering with the expansion or contraction of theother jacket or side, said well being lined with basic refractorymaterial and the portion of the cupola above the upper level of saidwater jackets and other opposite sides being lined with fire clayrefractory.

2. The combination, as defined in claim 1, in which the interior of thewater jacket progressively increases in cross-sectional area from thebottom to the top of the jacket.

3. The combination, as defined in claim 1, wherein each of said vanesextends between the inner and outer walls of the jacket and extendupwardly from one side wall of said jacket.

4. In a cupola furnace, a lining for said furnace extending from a levelabove the tuyeres of the furnace to a level above the melting zone ofthe cupola, said lining consisting of walls of basic refractory materialand watercooled jackets arranged alternately around the furnace, saidwalls and jackets having exposed faces facing the interior of thefurnace, the areas of the faces of said walls being similar in extent tothe areas of the faces of the jackets, and the walls and jacketscontacting at their ends in sliding relationship with each other,whereby each is free to expand and contract without disturbing theothers.

References Cited in the file of this patent UNITED STATES PATENTS 91,447Johnston Jan. 15, 1859 452,607 Hunts May 19, 1891 723,641 Boring Mar.24, 1903 842,663 I-Iixon Jan. 29, 1907 1,015,361 Tibbals et al. Jan. 23,1912 1,126,028 Kekich Jan. 26, 1915 1,758,478 Snyder May 13, 19302,238,036 Clutts Apr. 15, 1941 2,256,179 Thomson Sept. 16, 19412,270,297 Hensel Jan. 20, 1942 OTHER REFERENCES Pages 287 and 288 ofTrinks Industrial Furnaces, vol.

' 1, third ed., pub. by John Wiley and Sons, New York,

N. Y., copyright 1934.

Some Modifications in Cupola Design by Renshaw and Sargood, pages449-456, inclusive, of October 13, 1949 of Foundry Trade Journal.

